Keywords

Traits are not applied to subs until after they've been parsed, which means that traits cannot, say, alter how the signature is parsed, because the signature occurs before the traits.

For more advanced control over the parsing and behaviour of subs, you would need to create a new keyword. A keyword is just a Moo class which consumes the Kavorka::Sub role. Kavorka::Sub::Method and Kavorka::Sub::Fun are simple examples of such keyword classes.